Royal Marines will be deployed to prevent disruption of Sunday's Boat Race.
The troops will be equipped with inflatable craft and stationed at intervals
along the 4¼-mile course.

Their presence is intended to stop a repeat of last year’s incident when a protester halted the race by swimming into the path of the crews at Chiswick.

Trenton Oldfield, who was released from prison on electronic tag bail in February, has said he would rather take a ramble in the Cotswolds than jump into this year’s freezing water, but organisers fear a copycat disruption.

Race officials have spent the past 12 months considering how to safeguard their event. Water-borne security from the armed forces, who have been in the following flotilla of the last few Boat Races to provide safety cover, is preferred to more defensive measures.

David Searle, the Boat Race executive director, who last month told The Daily Telegraph that he hoped spectators would be vigilant for potential disruptors, said: “We are taking additional measures this year and have reviewed all our actions last year in detail.

“There will be an increased presence both on and off the water, including support from the Royal Marines, but as with any security plan I cannot disclose the exact details.

“What I would say to anybody thinking of disrupting the race is that it is unbelievably dangerous. You risk injuring yourself, the crews and the people following the race. Nobody wants that to happen.”

Sir Matthew Pinsent, who will be umpiring the race for the first time, said he would be opposed to any plan to fence off the river to foil intruders. “I wouldn’t want to be part of a Boat Race where it was impossible for someone to get access to the river, because that would mean crowd barriers,” he said.

“One of the joys of the Boat Race is that it is free, it is open, the riverbank is packed and every time the crews go under a bridge they are chock full.”

On a river still swollen by recent rain and high tides, debris might be a bigger problem than human obstructions.

Pinsent added: “I’ve done my best job with the crews to say that if I’m waving my red flag like a madman, they should stop,” Pinsent said. If a crew hit an obstacle we will halt them, get past, and restart the race as quickly as possible.”

The crews practised starts from stakeboats with Pinsent on Saturday, the boats each reaching a rate of over 50 in the first few strokes. Both were rapid, Oxford covering more distance in the first minute on the later tide, and Cambridge’s performances were some of the best they have done this week.

“As a crew we’ve become more of a unit,” said Light Blue cox Henry Fieldman. “We’ve got a much more powerful rhythm to depend on.”

Cambridge coach Steve Trapmore agreed: “It’s the best crew I’ve had in my time at Cambridge, and I’d say that extends to the squad as well. It’s been a very motivated and positively focused group. Everyone’s just as hungry to go out and produce a performance.”

The Dark Blues’ chief coach, Sean Bowden, has 10 Boat Race wins under his belt, eight with Oxford, from 17 races. He stopped labelling his crews “the best” long ago, but there is no doubt he is very satisfied with this year’s vintage, a very good sign for Oxford supporters.

“It helps having people who’ve been through the programme before,” Bowden said. “It helps having nice open-minded people like Malcolm Howard [the stroke] and the other new guys.”

Bowden has relished more continuity than in recent years, with five returning Blues in his squad, two of whom did not even make the crew. He has front-loaded his boat with two Olympians: Howard, of Canada, and British international Constantine Louloudis, who had a year out to go to the Olympics in 2012, at seven.

Oxford deny that revenge for last year’s eventful loss is a motivation. They were leading narrowly when the race was stopped, but Cambridge won after the restart.

“I never saw this year as a case of righting a wrong,” president Alex Davidson said. “I just don’t want to lose a race. I’m going to let the rowing do the talking on the day.”

Davidson did, however, admit that last year’s defeat had a personal impact. “I’m a competitive individual and maybe this year it crystallised a bit, having lost last year. I’ve been on the wrong side of that before: I don’t want to be on the wrong side again.”